• Journal of Korean Neurosurgical Society
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• v.55 no.5
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• pp.244-247
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• 2014

Objective : The aim of this study was to evaluate the microanatomy and histological features of the central myelin in the root exit zone of facial nerve. Methods : Forty facial nerves with brain stem were obtained from 20 formalin fixed cadavers. Among them 17 facial nerves were ruined during preparation and 23 root entry zone (REZ) of facial nerves could be examined. The length of medial REZ, from detach point of facial nerve at the brain stem to transitional area, and the thickness of glial membrane of central myelin was measured. We cut brain stem along the facial nerve and made a tissue block of facial nerve REZ. Each tissue block was embedded with paraffin and serially sectioned. Slices were stained with hematoxylin and eosin (H&E), periodic acid-Schiff, and glial fibrillary acid protein. Microscopy was used to measure the extent of central myelin and thickness of outer glial membrane of central myelin. Thickness of glial membrane was examined at two different points, the thickest area of proximal and distal REZ. Results : Special stain with PAS and GFAP could be differentiated the central and peripheral myelin of facial nerve. The length of medial REZ was mean 2.6 mm (1.6-3.5 mm). The glial limiting membrane of brain stem is continued to the end of central myelin. We called it glial sheath of REZ. The thickness of glial sheath was mean $66.5{\mu}m(40-110{\mu}m$) at proximal REZ and $7.4{\mu}m(5-10{\mu}m$) at distal REZ. Conclusion : Medial REZ of facial nerve is mean 2.6 mm in length and covered by glial sheath continued from glial limiting membrane of brain stem. Glial sheath of central myelin tends to become thin toward transitional zone.

• Journal of Genetic Medicine
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• v.10 no.2
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• pp.88-93
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• 2013

Alexander disease (ALXD) is a rare demyelinating disease of the white matter of the brain that is caused by a mutation in the glial fibrillary acidic protein (GFAP) gene. The overexpression of GFAP in astrocytes induces a failure in the developmental growth of the myelin sheath. The neurodegenerative destruction of the myelin sheath of the white matter is accompanied by an accumulation of abnormal deposits of Rosenthal fibers in astrocytes, which is the hallmark of ALXD. The disease can be divided into four groups based on the onset age of the patients: neonatal, infantile, juvenile, or adult. Early-onset disease is more severe, progresses rapidly, and results in a shorter life span than late-onset cases. Magnetic resonance imaging and genetic tests are mostly used for diagnostic purposes. Pathological tests of brain tissue for Rosenthal fibers are definitive diagnostic methods. Therapeutic strategies are being investigated. Ceftriaxone, which is an enhancer of glial glutamate transporter (GLT-1) expression, is currently in clinical trials for the treatment of patients with ALXD. To date, there are no clinically available treatments. The cause, pathology, pathophysiology, inheritance, clinical features, diagnosis, and treatment of ALXD will be reviewed comprehensively.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.295-300
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• 1993

Central nervous system of two dogs with natural canine distemper was investigated histopathologically and immunocytochemically with antisera to MBP, MAG and GFAP. Histopathologically, there were neuronal degeneration and diffuse gliosis in the cerebrum, vacuolar degeneration, hypertrophy of astrocytes and demyelination in cerebellar white matter adjacent to the 4th ventricle and optic tracts showing non-inflammatory demyelinating encephalomyelitis (Summers and Appel, 1987). Immunohistochemically, there was a concurrent disappearance of MBP and MAG in the well developed demyelinating lesion in the cerebellar white matter. At the margin of demyelination, Loss of both MBP and MAG varied on the stage of demyelinating process. GFAP-positive astrocytes were hypertrophied and contained canine distemper virus intranuclear inclusions. GFAP-positive fibers were increased at the early stage of demyelination, and then were not immunoreaeted at the well developed demyelination. Hypertrophic astrocytes with intranuclear inclusions were commonly identified in the interfascular layer without myelin vacuolation and demyelination. This is the first study of primary demyelination and astroglial reactions in natural CDE investigated using immunocytochemistry of two myelin proteins and GFAP. Concurrent loss of MBP and MAG suggest that the myelin sheath is the target in the demyelinating process in CDE.